Isolation and in-vitro and in-vivo characterisation of a mutant of Pseudomonas aeruginosa PAO1 that exhibited a reduced postantibiotic effect in response to imipenem.

Details

Serval ID
serval:BIB_02175ED277C5
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Isolation and in-vitro and in-vivo characterisation of a mutant of Pseudomonas aeruginosa PAO1 that exhibited a reduced postantibiotic effect in response to imipenem.
Journal
The Journal of Antimicrobial Chemotherapy
Author(s)
Majcherczyk P.A., Kunz S., Hattenberger M., Vaxelaire J., Zak O., O'Reilly T.
ISSN
0305-7453
Publication state
Published
Issued date
10/1994
Peer-reviewed
Oui
Volume
34
Number
4
Pages
485-505
Language
english
Notes
Publication types: Journal Article
Abstract
The postantibiotic effect (PAE) is the persistent inhibition of bacterial growth after a brief exposure to an antibiotic. Most beta-lactams do not induce a PAE for Gram-negative bacteria, but PAEs have been reported for carbapenems and penems. This study investigated the effect of sequential doses of imipenem on the PAE for Pseudomonas aeruginosa and Escherichia coli cultures in a chemostat. The PAE for the bacterial population did not change even after six successive exposures to imipenem. Nevertheless, screening of colonies isolated after repeated drug exposure identified a single P. aeruginosa mutant whose imipenem PAE was shortened, although the MIC was unchanged. The PAEs for the parent and mutant were studied in vitro in batch culture by monitoring: (i) viable counts; (ii) electrical impedance of the culture medium; (iii) incorporation of radiolabelled N-acetyl-D-glucosamine and (iv) cell volume changes. PAEs for the parent and mutant were found to be significantly different by all in-vitro methods used. Moreover, the median cell volume in antibiotic-exposed cultures remained much smaller and less heterogeneous than in the control cultures, even though both cultures were growing at the same rate. The mutant was found to have a reduced expression of a 52 kDa outer membrane protein. These observations suggest that factors in addition to suppression of bacterial growth should be considered when studying the PAE. The PAEs of imipenem for the parent and mutant were studied in a thigh infection model in leucopenic mice. Similar PAEs were observed in vivo for both parent and mutant in one experiment and no PAEs for either organism were found in a second experiment. This study showed that although the PAE is a stable in-vitro phenomenon, the lack of correlation between the in-vitro and in-vivo results warrants caution in attributing clinical significance to the PAE of imipenem.
Keywords
Acetylglucosamine/metabolism, Animals, Bacterial Outer Membrane Proteins/metabolism, Electric Conductivity, Escherichia coli/drug effects, Escherichia coli/metabolism, Female, Imipenem/pharmacokinetics, Imipenem/pharmacology, Leukopenia/metabolism, Leukopenia/microbiology, Mice, Mice, Inbred Strains, Microbial Sensitivity Tests, Mutation, Pseudomonas Infections/drug therapy, Pseudomonas Infections/microbiology, Pseudomonas aeruginosa/drug effects, Pseudomonas aeruginosa/genetics
Pubmed
Web of science
Create date
24/01/2008 13:54
Last modification date
20/08/2019 12:24
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